This invention relates to a rear brake unit for a beach buggy, particularly to one having a brake disc of high strength and with no fear of disfiguring, having comparatively better effect for braking.
Common conventional beach buggies have a rear wheel brake unit for controlling to reduce speed and stop the buggy. Its operating method includes a brake wire pulling brakes members of the rear wheel axle to expand to friction with an inner surface of a brake drum rotating with the axle of the rear wheels, achieving speed reduction and stop of the buggy.
A known conventional rear brake unit of a beach buggy has a structure shown in FIGS. 1 and 2, including a axle sleeve 10 fitted around a rear wheel axle 50, a brake disc 20 welded with an outer end of the sleeve 10 by means of CO.sub.2, a position rod 201 fixed on the brake disc 20 and an activating rod 202 connected to and pulled by a brake wire 2031 (not shown in Figures), two semicircular brake members 203 located beside the brake disc 2 fixed between and pulling to expand or loosening the brake members 23. The two semicircular brake members 23 have one end clamping the position rod 201 of the brake disc 20, not separating from the brake disc 20, and the other end clamping a flat activating block 2021 of the activating rod 202, as shown in FIG. 2. Further a brake drum 30 surrounds the two semicircular brake members 203 engaging and rotating with the rear axle 50, which has its end engages with the brake drum 30. Further, a dirt cover 40 is fixed to hide the brake drum 30, preventing dirt from entering the brake drum 30 to avoid undesirable wear and tear to affect braking effect.
The conventional brake disc 20 and the brake drum 30 are generally made of iron, and the brake disc 20 and the shaft sleeve 10 are welded together with CO.sub.2, but the brake disc 20 may often disfigure in welding process. Once the brake disc 20 disfigures, an angle inclination may be formed to the shaft sleeve 10, not vertical, causing the position rod 201 of the brake disc 20 and the activating rod 202 also incline, not parallel to the axle 50 worsening contact of the brake members 203 with the brake drum 30 and lessening the dimensions of mutual friction and braking effect. In addition, the brake members 203 may bias to easily produce friction against the iron brake drum 30 and thus heighten temperature to make noise. In addition, when the brake wire pulls the activating rod 202 to activate the brake members 203, the brake members 203 can only partly touch and friction with the brake drum 30 owing to the inclined activating rod 202, causing the brake disc 20 seriously disfigure under unbalanced friction. Furthermore, the brake drum 30 is hidden in the brake cover 40, forming a double-layer design, the brake drum 30 and the brake members 203 have to be reduced in their size, as the brake unit cannot be enlarged in order not to affect the other structures. Subsequently, the brake drum 30 is made to have a smaller inner diameter and thus also a smaller dimensions in the inner space, lessening accordingly the friction dimensions between the brake members 203 and the b rake drum 30 to lower braking effect. This structural problem of the conventional rear brake device has to be solved.